To Scott and the girls (and everyone else) concerning big spleens... I often get questions about big spleens in ferrets. This is a very common finding on physical exam - notice I say "finding" rather than "problem". No one is quite sure about the cause of this finding - some people think it may be viral, some believe it may result from chronic smouldering infection. I look at quite a few spleens on a yearly basis. Over 90% do not have tumors - they are simply a combination of congestion with blood and a large number of blood cell precursors - immature cells which make red and white blood cells. In general, the presence of immature blood cells suggests a demand for these cells elsewhere in the body and suggests either anemia or chronic inflammation. Most of the animals are not anemic, so chronic inflammation is the most likely culprit. (My personal view is that the presence of Helicobacter mustelae, a common gstric infection in ferrets may have something to do with splenomegaly. Helicobacter is renowned for causing a significant, but largely asymptomatic inflammatory lesion in the stomach.) The other 10% of enlarged spleens generally do fall into the neoplasm category - primarily lymphosarcomas, rarely sarcomas of other types. The only way to tell what is going on in a spleen is generally to remove it and have it looked at by a pathologist. Aspirating a few cells out of it with a needle may give a diagnosis inthe case of splenic lymphosarcoma, but is not very useful overall. The way I proceed with the big spleen - if the animal is lethargic, or won't eat, and other causes have been ruled out, then I would suggest removing the spleen and having it evaluated. However, if other diseases are present, or the animal is doing well, the presence of a big spleen shouldn't necessitate surgery. Removal of an enlarged spleen in a lethargic ferret generally restores vitality. A grossly enlarged spleen will cuases compression and displacemnt of surrounding organs. Imagine if your spleen wiehged 40 pounds - you wouldn't want to play much either!!! Bruce Williams, DVM Department of Veterinary Pathology [log in to unmask] Armed Forces Institute of Pathology (202) 576-2453/2454 Washington, D.C. 20306-6000 [Posted in FML issue 0869]